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Google says..H2O2 kills fungus gnats/thrips larvae

L

little-soldier

Active member
Apparently drenching you soil with 1 part hydrogen peroxide mixed with 4 parts water kills fungus gnats and even thrips larvae. But then again, google says so so Im skeptical. Anyone tried this before?
Reason Im asking is I recently bought new soil and got thrips in my grow room now. Im looking for a way to sterilise soil for both fungus gnats and thrips before using it from now on and was thinking either drenching with neem oil or H2O2. Google also says it kills the eggs :bow:

Im really starting to wonder how these commercial growers sterilise their new soil before use. No way they shove all that dirt in a huge oven lol.
 
f-e

f-e

Well-known member
Mentor
Veteran
I wonder how many parts hydrogen peroxide, their hydrogen peroxide is.
 
G

Gauss

little-soldier said:
Im really starting to wonder how these commercial growers sterilise their new soil before use. No way they shove all that dirt in a huge oven lol.
Click to expand...

FWIW most of them use disposable coco/grodan blocks on flood tables or are doing straight hydro/aero.
 
M

moose eater

Doesn't the H2O2 in regular application also raise the levels of salts, as well as kill many beneficial micro-orgs?

I've used H2O2 in the past, specifically for fungus issues, and there was a point of diminishing returns, so to speak.
 
Dropped Cat

Dropped Cat

Six Gummi Bears and Some Scotch
Veteran
In my coco DTW I use bleach, as the H2O2 was not as effective
in the reduction of gnats.

I also pasteurize all coco to minimize infestations and have not had
more than one or two flyers in a couple years.
 
L

little-soldier

Active member
I will stay away from bleach because I like to smoke you know...
How would I go about pasteurizing coco/soil if I have a big amount and a small oven?
 
M

moose eater

Black tarps in hot sun might work; check temps inside tarps/visqueen to see if you're reaching prescribed temps..
 
buzzmobile

buzzmobile

Well-known member
Veteran
moose eater said:
Black tarps in hot sun might work; check temps inside tarps/visqueen to see if you're reaching prescribed temps..
Click to expand...

In most locations clear visqueen will develop higher temps than black.
Soil Solarization for Gardens & Landscapes

Plastic material. In general, transparent or clear plastic is most effective for solarization, as the heating rays from the sun will pass through the sheet and be trapped to heat the soil below.

Usually black plastic is less effective because it absorbs and deflects part of the heat, rather than trapping as clear plastic does. However, in cooler or coastal areas, black plastic is sometimes better than clear, because weeds won’t grow beneath it, as they will under clear plastic when the air temperatures are too low to kill them. In this case, the black plastic should be left in place for several weeks during the hottest part of the year.
Click to expand...

In Alaska, black would be the choice.:tiphat:
 
Dropped Cat

Dropped Cat

Six Gummi Bears and Some Scotch
Veteran
little-soldier said:
How would I go about pasteurizing coco/soil if I have a big amount and a small oven?
Click to expand...


I use a small rice cooker with a few cups of water to simmer the coco for 20-30 minutes.

I know large scale growers that use 5 gallon commercial rice cookers,
way less expensive than fighting a gnat infestation.

Avoid dry cooking coco, that's asking for a smokey mess, lol.


moose eater said:
Black tarps in hot sun might work; check temps inside tarps/visqueen to see if you're reaching prescribed temps..
Click to expand...


Outside cooking can reintroduce other pathogens, but if the area is
screened and completely removed from the ground, then that
can be useful for large batches, I suppose.
 
therevverend

therevverend

Well-known member
Veteran
I used to use diluted peroxide for my soil containers indoors. To get rid of my soil gnats and my chemist buddy said the extra oxygen boosted plant growth. It worked, my plants were healthy and the gnats were wiped out. If it damaged the beneficial microbes I didn't see evidence. I did dilute quite a bit but I can't remember the ratio because it was quite a while ago.

With any of these tricks I wouldn't go overboard, we think if some is good more is better. Or if something causes damage throw it away. Moderation and patience are the way to go with plants.
 
L

little-soldier

Active member
Im wondering if the rice cooker method also kills the eggs and how?
But wouldn't it be easier to just drench the soil with a strong pool shock solution (Calcium Hypochlorite)? Could be anything like Neem oil, H2O2, alcohol and flush your soil with water before planting.
 
webwiller

webwiller

Member
Sorry, I might be completely wrong but....if you can you could boil your medium 5 minutes. If you have a 40 liters metal bucket of some sorts (here we use those which contained wall paintings. Some have plastic buckets, others have metal ones. We build a small pit with few bricks, light a decent fire and put a bucket of water to cook. When it boils you can put your medium in (some at the time) and boil it for 5 minutes. With a colander, you can take medium out after sterilization and proceed with more. I bet it's a healthy, biological way to sterilize at home.
 
GMT

GMT

The Tri Guy
Veteran
? I just water the compost and leave it open somewhere warm. Anything in the compost hatches. Anything that flies, flies away, anything that eats plants, starves. Then its clean. Do you all buy supplies and use them straight away?
 
MJPassion

MJPassion

Observer
ICMag Donor
Veteran
H2O2 works fairly well IME.

Mixed 1 to 4 or 1 to 5 is what I normally use when I have a gnarly gnat infestation.

To get everything it is best to drench more than once.

Once the infestation has diminished, re-innoculate your soil with beneficials.


H2O2 has the added advantage that if you are suffering from any sort of anerobic/septic conditions it can potentially clear them up as well.
 
L

little-soldier

Active member
Only problem with h2o2 is the cost. 1 part h2o2 and 5 part water when you have to drench 200 liters of coco can be expensive. In the video the guy mentions that you can also freeze the soil but would'nt the bugs just stay dormant and wake up once the soil gets back to room temperature? Im thinking maybe if the soil freezes too quick the bugs die? Would that make sense anyone?
 
M

moose eater

Lice and other problematic critters have been dealt with via freezing for years. As in treating trichinosis and parasites in meat products, there's often a 'time frozen' that correlates to specific temperature ranges.

I believe you can buy H2O2 in large bulk quantities, though I've typically bought it in 2-packs of 1-liter bottles, at warehouse stores such as Costco or Sam's for as little as about $2.50 or so per 2 liters. Meaning (at a 1:4 ratio) just over a half bottle (by my mental math, and no calculator at the moment) would treat a gallon of H2O; correct me if I'm wrong, I'm growing a thicker skin these days ;^>)

So, based on past pricing, I used to get 8 liters for about $10. Or 16 liters for $20, give or take $5.

Those were all 3% solutions.

I don't know if larger quantities than those I referenced would be of the medical grade you probably desire, though.

Good luck. And hope the little bastards don't have goose down vests handy.
 
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